In the framework of the latter approach and using classical recursive relations for wave propagation in thin films [1]}, the reflection coefficient \(r_\text{st}\)  of a particle monolayer above a layered substrate (made of isotropic materials, to disregard polarization conversionMultilayered substrates with anisotropic materials could be considered as well, in which case the reflection and transmission coefficients should be written as \(2 \times 2\)  matrices for TE and TM (or s and p) polarizations. Several publicly available codes can be used for the purpose [2]}, [3]}.) is simply given by
\(r_\text{st} = r_\text{coh} + \frac{r_\text{sub} t_\text{coh}^2 \exp [2i k_0 n_\text{b} a \cos (\theta _\text{i})]}{1-r_\text{coh} r_\text{sub} \exp [2i k_0 n_\text{b} a \cos (\theta _\text{i})]},\) 
